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Finding the Fourth Proportional to 640.28, 960.69 and 409.11

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Solution

The fourth proportional to 640.28, 960.69 and 409.11 is: 613.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.28 : 960.69 = 409.11 : x
  2. Step 2: Convert to fraction form
    640.28/960.69 = 409.11/x
  3. Step 3: Cross multiply
    640.28x = 960.69 × 409.11
  4. Step 4: Simplify right side
    640.28x = 393,027.89
  5. Step 5: Solve for x
    x = 393,027.89/640.28
  6. Step 6: Final answer
    x = 613.84

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.